1. Field of the Invention
In order to ensure the maximum efficiency of an improved engine devised as an automobile exhaust emission control effort or when it is desired to obtain the optimum cleaning of exhaust gases by a catalyst in an engine equipped with an exhaust gas cleaning catalyst for exhaust emission control purposes, the air-fuel ratio of the mixtures supplied to the engine through the carburetor must always be controlled at the correct value. The present invention relates to an air-fuel mixture ratio correcting system for an automobile internal combustion engine carburetor which meets these requirements.
2. Description of the Prior Art
It is known in the art that the air-fuel ratio of the mixtures supplied into the cylinders of an engine has a great effect on the quality of ignition and combustion of the mixtures as well as on the exhaust gas composition, and various efforts have heretofore been made toward accurate controlling of the air-fuel ratio of the mixtures fed to an engine. These efforts range from the improved accuracy of finishing for the carburetor component parts and increased carburetor adjustments to efforts toward more accurate methods of measuring the amount of air drawn into an engine and correspondingly accurate fuel metering methods in the case of fuel injection type fuel feed systems.
However, these methods are primarily concerned with the improvements of accuracy of measuring or metering the quantity of air and fuel supplied to an engine and therefore these methods can hardly be said to have covered all the possible situations in consideration of changes in the atmospheric conditions, i.e., changes in the atmospheric pressure temperature, and humidity.
Similarly, as regards the supply of fuel, it can be hardly said that the computation of changes in the theoretical air-fuel ratio due to changes in the specific weight of the fuel, the amount of air contained in the fuel and the composition of the fuel has been made to a satisfactory extent. If a system were constructed which would meet all of these requirements technically, such a system would become exceeding high in manufacturing costs and very complicated in construction and therefore such a system would inevitably be unsuitable for use as a fuel system for internal combustion engines of the type which are now in wide use.